The focus is outboard motors of smaller size—usually below 10 HP and where typical use applies to small craft of lengths generally 6 to 25 ft where and especially where care is needed to prevent unstable conditions that might arise from moving one's weight to the near proximity of the outboard motor, or by twisting one's body to reach parts of the outboard motor. Canoes and kayaks are longer craft that due to their narrow beam are subject to stability problems from such crew movements. Smaller craft of length 12 ft and under, and of a typical width, are also subject to stability impacts from shifting crew weight. Finally, most smaller boats that use motors have the motor mounted on or near the stern— the rear end of the craft. If the crew moves aft to manage the motor operation, than weight on the stern both makes the boat less efficient to propel and causes handling problems in windy conditions. Finally, moving one's weight to the rear of the craft to manipulate latches, or to turn the motor around, depending on the specific craft and sea conditions, can decrease freeboard, inviting a swamping or sinking outcome. So in short, it is important to safety, comfort, efficiency and control to maintain crew in a stable position in a boat and located so that their weight maintains proper trim.
Selecting reverse will cause a motor to pivot up to the rear, and out of the water by means of the reverse thrust from the propeller. When this happens, reverse thrust is lost and/or unsafe in-air rotating propeller conditions exist. So motors that have reverse all have some means of latching the motor in the lowered position to prevent unintentional raising of the motor. Outboard motors that have a reverse function all currently require the operator to move close to the motor, either for lifting and lowering the motor, or for selecting reverse by turning the motor around to operate backwards. Some motors without reverse do not, but then the benefits of having a reverse function are lost.
Outboard motors are generally designed to tilt from an in-use position where the propeller is immersed, to a lifted position where the propeller is raised. The action of raising the motor to a lifted position is usually accomplished by releasing a latch proximal to the clamp, reaching to the rear of the motor housing and pulling to lift, especially for motors fitted with a reverse capability. Once in a lifted position, another latch, or the same latch if it is a dual-purpose latch, maintains the lifted position. To lower the motor, another latch or the same dual purpose latch near the clamp is released by hand, and the motor housing is pushed until the propeller end is properly immersed for operation. In these instances, it is required that the user access the motor housing and release latches which may require them to move to the end of the boat where the motor is mounted.
Some outboard motors have no means of latching the motor in the upright or lowered position. But these motors have no reverse function and they require the user to reach back to the motor housing to heave the motor to a lifted condition or to push the motor to a lowered position.
Some outboard motors similarly have no means of latching the motor in the upright or lowered position and limited reverse functionality. In this instance, a geometrical relationship between the motor pivot point and the tiller pivot allows the motor to be lowered to an immersed position by pushing on the tiller, and allows the user to raise the motor by pulling on the tiller arm (see U.S. Pat. No. 8,597,066, US20120064783, US20140008512), allowing the user to remain in a safe seated position while operating the tilt functions of their motor. These motors may have a reverse function by employing a spring latch that releases at some force level. However this limits the reverse thrust to a level quite low; since the distance from the pivot point to the propeller is large compared to the distance from the pivot point to the spring latch. So the force resistance of the spring latch must be proportionally higher than the reverse thrust. This makes the torque required to raise the motor quite high in practice. For example, if the distance from the pivot to the propeller is 15 inches (a normal short shaft motor) and the distance from the pivot to the spring latch is 5 inches, than a 10 lb reverse thrust equates to a 30 lb latch requirement. Assuming the acting radius of the tiller arm pivot solution in U.S. Pat. No. 8,597,066 is also 5 inches, that would require a 30 lb pull on the tiller arm to release the spring latch. This is a high force requiring a significant amount of effort.
In some instances, reverse is selected by rotating the motor 180 degrees which redirects the thrust backwards. In this cases, the motor shaft engages a hook when rotated to prevent raising when deployed for reverse. This hook releases when the motor is again turned around to the forward position allowing the motor to raise as needed without manipulation of another latch. However, this solution requires the user to sit very close to the motor to rotate the motor for reverse, and even these motors generally do not allow raising and lowering by pulling and pushing on the tiller arm and therefore can cause instability as described in scenarios above.
In some instances reverse is actuated by a twist of the throttle or changing of a direction selection lever on the motor. In these instances, the motor has no need to be twisted around for reverse. However, a latch is required in order to keep the motor in a lowered position against the rearward thrust of the propeller. So these motors typically have two latch positions, one where the reverse resistance feature is enabled, and one where it is disabled enabling a “kick-up” mode. Before beaching a boat fitted with such a motor it is necessary to remember to place this latch in a kick-up mode.
For other cases, such as commonly employed in trolling motors, the motor is latched its position at all times unless a latch is manually held in a release position. With such solutions there is a risk of the motor remaining in a latched down position when encountering the beach or underwater obstructions and the result can be sudden instability, sudden stops causing people to be thrown forward, damage to the motor or damage to the boat where the motor is mounted.